4. Rules to Remember:
z When writing a whole number as a fraction,
place the whole number over one.
2 tablets = 2 / 1
10 mgs = 10 / 1
100 mgs = 100 / 1
5. Rules to Remember:
z When moving a decimal, to the right or left of “ZERO”, double check your
answer.
*Whole numbers to left (of zero)
-units
-tens
-hundreds
-thousands
-ten-thousands
*Decimal fractions to the right (of zero)
-tenths
-hundredths
-thousandths
-ten-thousands
6. Rule to Remember:
z When changing a decimal point to a
percentage, move the decimal point (2)
places to the right.
0.45 = 45%
0.06 = 6%
0.008 = 0.8%
7. Rule to Remember:
z You multiply a fraction by 100 to obtain the
percent.
1 / 2 (X) 100 / 1 = 50%
1 / 8 (X) 100 / 1 = 12 ½ %
8. Rule to Remember:
z When changing a percent to a fraction, divide
the percent by a denominator of 100 (N/D).
50% = 50 / 100
66 2/3% = 200 / 3 (X) 1 / 100 = 2 / 3
* Reverse the divisor and multiply with percents that are mixed fractions
9. Rule to Remember:
z When calculating the percent of a whole
number, change the percent to a decimal
and multiply by the whole number.
200% of 35 = 2.00 (X) 35 = 70.0
5% of 25 = 0.05 (X) 25 = 1.25
10. Rule to Remember:
z Review roman numerals because
medications are sometimes ordered using
roman numerals.
ASA V grains q6h orally
Tylenol X grains q6h orally
11. Rule to Remember:
z When rounding off numbers < 5 round down
and =/> 5 round up.
45.88 = 46.0
10.35 = 10.0
REMEMBER: Look at the medication you are giving
because some medication (injections) can be
given in “tenths” (example: 1.2 ml) or
“hundredths” (example: 0.23 ml).
12. Conversions:
z 1 liter (L) = 1000 ml (milliters)
z 1 gram (g) = 1000 mgs (milligrams)
z 1 mg (milligrams) = 1000 mcgs (micrograms)
z 1 gram (g) = 15 grain (gr)
z 1 grain (gr) = 60 mg (milligrams)
z 1 dram (dr) =4 ml (milliters)
z 1 ounce (oz) = 30 ml (milliters)
z 1 tsp (teaspoon) = 5 ml (milliters)
z 1 tbs (tablespoon) = 15 ml (milliters)
z 1 kg (kilogram) = 2.2 lbs (pounds)
z 1 inch = 2.54 cm (centimeters)
z 16 ounces (ozs) = 1 lb (pound)
z 1 cup = 8 ounces (ozs)
z 1 ml (milliter) = 15 minims
z 1 tsp (teaspoon) = 5 ml (milliters)
z 1 tbs (tablespoon) = 15 ml (milliters)
z 1 drop (gtt) = 15 minims
13. IV Drip Rate Calculation:
z mls to infuse (X) drip factor
------------------------------------ divided by = gtts/min.
minutes (min.) to infuse
14. Client Rights:
z Right client
z Right drug
z Right dose
z Right time
z Right route
z Right documentation
z Right to refuse treatment
15. Drug Names:
z Generic Names are official names used by
the drug companies (Acetaminophen).
z Trade or Brand Names are names assigned
to a product by its manufacturer (Tylenol).
16. Recommended Volume for
Administration Per Sites:
z Intradermal = 0.1 ml (example PPD, allergy
testing)
z Subcutaneous injection = 0.5-1.0 ml per site
z Intramuscular injection = 3.0 ml per site
(1 ml in the deltoid)
z IV injection (IV push) = 1-60 ml
17. A Calculation Method: use the
calculation method easiest for you
z Method:
1. Medication Available: 250mg tablets
250mg (:-is to) 1 tablet
2. Medication Ordered: 500mg (how many tablets you would give)
500mg (:-is to) (X) tablet
3. Formula:
Ordered (Desired)
---------- (X) Supplied (tsp, ml, tablet, capsule, etc.)= X
Available (Have)
4. 500 mg : X tablets 500 (X) 1 500
--------------------------- (cross multiply) = --------------- = ------- = 2 tablets
250 mg : 1 tablet 250 (X) X 250
5. Checking Accuracy of Answer:
250mg X (ordered medication) 500
--------- (X) ----------------------- = -------- = 500mg (your answer is correct)
1 tablet 2 tablets 1
REMEMBER: Always check your answer for accuracy (step 5). An error in calculation can result in life
threatening complications for the client.
18. Calculation Method: use the
calculation method easiest for you
z Method:
1. Medication Available: 250mg tablets
250mg = 1 tablet
2. Medication Ordered: 500mg
500mg = (X) tablets
3. Formula:
250mg 500mg 500mg
--------- (X) ---------- = ------------- = 2 tablets
1 tablet x tablets x 250mg
4. Checking you answer for accuracy:
250mg x=ordered medication (500mg) 500
--------- (X) ------------- = ----------- = 500 mg (your answer is
1 tablet 2 tablets is your answer 1 is correct)
REMEMBER: Always check your answer for accuracy (step 4). An error calculation can
result in life threatening complications for the client.
19. Calculation Method:use the calculation
method easiest for you
Available Ordered *Ordered Medication: 100 mg Lasix
1. Medication Medication PO QD
50 mg Lasix 100 mg Lasix Available Medication: 50 mg Lasix in
---------------- ------------------ 1 ml
1 ml X ml How many ml would you
2. Cross multiple administer? 2 ml = 100 mg
100 mg (times) 1 ml 100
--------------------------- = ------ = x is 2 ml (how many ml (=) 100 mg Lasix)
50 mg (times) x ml 50
3. Check your work!
50 mg Lasix x mg Lasix (medication ordered)
----------------- ---------------
1 ml 2 ml (to administer 100 mg Lasix)
4. Cross multiple
50 mg (times) 2 ml 100
------------------------- = -------- = 100 mg Lasix (this is the medication ordered and your
1 ml (times) x mg 1 answer of 2 ml is correct)
20. Practice Question:
z The physician orders Ampicillin 500mg q6h
orally (po). Ampicillin is available: 250mg
capsule (cap). How many capsules would
you administer q6h?
*check answer:
21. Practice Question:
z The physician orders Lanoxin 0.25mg IM
every day. Lanoxin is available: 0.5mg per
2 ml. How much Lanoxin would you
administer IM ?
*check answer:
22. Practice Question:
z The physician orders Theophylline 160mg
q6h orally (po). Theophylline is available:
80mg per 15 ml. How much Theophylline
would you administer q6h?
*check answer:
23. Practice Question:
z The physician orders Morphine 5mg IM q4h.
Morphine is available: 1grain per 5 ml. How
much Morphine would you administer?
1 grain = 60mg
Morphine is available: 60mg per 5 ml
*check answer:
24. Practice Question:
z The physician orders Morphine 1/100 grain
(gr) IM q6h for abdominal pain. Morphine is
available: 0.5mg per 0.5 ml. How much
would you administer?
1/100 grain = 0.01 grain = 0.6mg
*check answer:
25. Practice Question:
z The physician orders 1000 ml 0.9% Normal Saline to run over
10 hours. The IV tubing drip rate is 10 drops (gtts) per ml. How
many drops per minute would the IV be regulated to?
1000 ml (X) 10 gtts per ml = 10000 gtts in 1000 ml
------------------------divided by
60 minutes (X) 10 hours = 600 minutes (min.)
10000 gtts in 1000 ml / 600 min. = 16.7 gtts per min. (round up)
17 gtts per min.
*check answer:
26. Practice Question:
z The physician ordered Keflex 2500mg orally
(po) in divided doses q6h every day. Keflex
is available: 250mg per 5 ml. How much
would you administer per dose?
2500mg / (4) doses (q6h) = 625mg per dose
*check answer:
27. Practice Question:
z Conversions:
15 ml = _____teaspoons (tsps)
45 ml = _____ounces (ozs)
8 ounces (ozs) = _____mls
76 kilograms (kgs) = ______lbs (pounds)
60 inches = _____centimeters (cms)
